When accident happens, the most common situation might be the human body get hurt and some cuts or wounds are made with blood, so that stopping bleeding is the initial action of the first aid.
Usually, the slight trauma, like cut and wound, caused in daily life, is bleeding caused in the blood capillary or slight vein. The most common way to stop bleeding is to apply direct pressure on the bleed, and to band the wound then, so that the blood on the wound can have a spontaneous clot and callus. Moreover, when the trauma is more serious, such as injury of vein or slight artery, the bleeding volume becomes more and is more difficult to clot, so that in addition to direct pressure, lifting up the injured limb or applying point pressure for stopping bleeding have been used simultaneously. For the most severe situation, for example, the limb is broken to cause a large amount of blood loss, the most important thing is to keep alive, so that the emergent method is to use tourniquet to stop bleeding. But, as known, applying tourniquet might easily kill the tissue, so that it should be the last resort to use.
The principle of tourniquet is to constrict or compress the vicinity of the bleeding portion for stopping blood loss. Since it is usually used in the emergency, the essential conditions of a well-designed tourniquet should be easy to arrange with capabilities of providing sufficient strength, rapid fixing and easy to disengage. There are many types of the tourniquets. One of them is TWP No. M263082, entitled “Improved structure of tourniquet”, including a release buckle with a tongue and an engaging portion which are connected by a band. When using this tourniquet, the band is applied circumferentially upon the bleeding portion, and the tongue and the engaging portion are engaged together for fixing the band. Then, through a circling structure in the tongue, the band can be tightened by pulling so as to stop bleeding. However, this application could not provide a strong pressure and might easily become loose owing to an external touch to contact the upright tourniquet. Another example is TWP No. M318404, entitled “Adjustable tourniquet”, in which two ends of a band are respectively connected to a first housing and a third housing, which are buckled together to loop the band, and through a structure in the third housing, the band can be tightened by applying force. Further, it is characterized in that a second housing is included, wherein an axle of the second housing is passed through a hollow axial tube of the first housing, and the first and the second housings have a rejecting element, plural ratchets and a driving element, so that when the second housing moves by pivoting about the axial tube, through the orientation mechanism of the ratchets, the band can have a slight adjustment. However, when applying this structure, the user might easily touch the sliding portion so as to move the driving element, thereby loosing the tightening strength. Beside, the structure of hollow axial tube cooperating with the axle is complicated, and the overlapped rejecting element and the driving element form a thicker structure which increases the collision possibility, and thus, the loosing possibility would be present.